The invention relates to brush seals and methods of using brush seals.
Brush seals are utilized in a wide variety of operating environments to provide a seal between a housing and a rotating shaft disposed in the housing, for example. Illustratively, brush seals may be utilized in power generation turbines.
For example, the rotating shaft may be a rotor in the power generation turbine. Brush seal construction typically includes thousands of bristles. Each bristle possesses a very small bristle diameter. Collectively, the bristles of the brush seal form a seal.
Brush seals are typically used in a wide variety of industrial applications. Such applications include gas turbine applications or steam turbine gas applications. Further, brush seals operate in severe flow environments, such as in high turbulence flow environments, unsteady flow fields, or flow environments in which there are very high swirl ratios. All these factors contribute to the instability and degradation of the bristles in the brush seal.
The thousands of bristles included in a brush seal are typically grouped together in a bristle pack, for example. Once the bristle pack becomes unstable, it should be appreciated that the life of the brush seal is significantly reduced due to the HCF (high-cycle fatigue) failure of bristles. HCF failure can occur very quickly when a component has a high level of response to a stimulus that occurs at the natural frequency of the component. In order to prevent bristle instability from occurring, one can either improve the brush seal design and/or improve the flow environment in which the brush seal will be operating.
In accordance with one aspect, the invention provides a brush seal assembly for reducing adverse fluid flow effects to a brush seal, the brush seal assembly comprising a support housing having a passage; a rotating shaft disposed in the passage of the support housing, the rotating shaft including a shaft body having a periphery and an annular tooth extending around the periphery of the shaft body; an annular brush seal including a plurality of bristles extending around the shaft body, each of the plurality of bristles attached to and extending from the support housing in the passage towards the rotating shaft; and an annular abradable material portion being constructed of an abradable material, the abradable material portion having a groove extending around an inner periphery thereof, the abradable material portion disposed in the passage around, and proximate to, the tooth of the rotating shaft such that the tooth of the rotating shaft is disposed in the groove of the abradable material portion.
In accordance with a further aspect, the invention provides a brush seal assembly for reducing adverse fluid flow effects to a brush seal, the brush seal assembly comprising a support housing having a passage; a rotating shaft disposed in the passage of the support housing, the rotating shaft including a shaft body having a periphery and an annular tooth extending around the periphery of the shaft body; an annular brush seal including a plurality of bristles extending around the shaft body, each of the plurality of bristles attached to and extending from the support housing in the passage towards the rotating shaft; and an annular honeycomb assembly being constructed of a plurality of walled cells and having a groove extending around an inner periphery thereof, the honeycomb assembly disposed in the passage around, and proximate to, the tooth of the rotating shaft such that the tooth of the rotating shaft is disposed in the groove of the honeycomb assembly.
In accordance with a further aspect, the invention provides a method for reducing exposure of a brush seal to adverse fluid flow effects, the method comprising the steps of providing a support housing having a passage; providing a rotating shaft disposed in the passage of the support housing, the rotating shaft including a shaft body having a periphery and an annular tooth extending around the periphery of the shaft body; providing an annular brush seal including a plurality of bristles extending around the shaft body, each of the plurality of bristles attached to and extending from the support housing in the passage towards the rotating shaft; providing an annular honeycomb assembly, the annular honeycomb assembly disposed in the passage around, and proximate to, the tooth of the rotating shaft, the honeycomb assembly being constructed of a plurality of walled cells; circulating fluid in a space between the support housing and the rotating shaft, the circulated fluid possessing pressure fluctuations, the tooth and the honeycomb assembly each being positioned between the circulating fluid and the brush seal; and contacting the honeycomb assembly with the annular tooth so as to reduce exposure of the brush seal to the pressure fluctuations in the circulated fluid.
In accordance with a further aspect, the invention provides a brush seal assembly for reducing adverse fluid flow effects to a brush seal, the brush seal assembly comprising a support housing having a passage; a rotating shaft disposed in the passage of the support housing, the rotating shaft including a shaft body having a periphery and an annular tooth extending around the periphery of the shaft body, the shaft body and the annular tooth being integrally formed; an annular brush seal including a plurality of bristles extending around the shaft body, each of the plurality of bristles attached to and extending from the support housing in the passage towards the rotating shaft; and an annular honeycomb assembly being constructed Of a plurality of walled cells and having a groove extending around an inner periphery thereof, the honeycomb assembly disposed in the passage around, and proximate to, the tooth of the rotating shaft such that the tooth of the rotating shaft is disposed in the groove of the honeycomb assembly; an annular second honeycomb assembly, the second honeycomb assembly being constructed of a plurality of walled cells and having a groove extending around an inner periphery thereof; and the rotating shaft further including an annular second tooth extending around the periphery of the shaft body and spaced from the first tooth, the second honeycomb assembly disposed in the passage around, and proximate to, the second tooth such that the second tooth of the rotating shaft is disposed in the groove of the second honeycomb assembly; wherein the brush seal is disposed between the first honeycomb assembly and the second honeycomb assembly.
In accordance with a further aspect, the invention provides a method for reducing exposure of a brush seal to fluid fluctuations in an industrial gas turbine, the method comprising the steps of providing a support housing having a passage; providing a rotating shaft disposed in the passage of the support housing, the rotating shaft including a shaft body having a periphery and an annular tooth extending around the periphery of the shaft body, the shaft body being integrally formed with the tooth;providing an annular brush seal including a plurality of bristles extending around the shaft body, each of the plurality of bristles attached to and extending from the support housing in the passage towards the rotating shaft; providing an annular honeycomb assembly, the annular honeycomb assembly disposed in the passage around, and proximate to, the tooth of the rotating shaft, the honeycomb assembly being constructed of a plurality of walled cells, the honeycomb assembly further including a groove extending around an inner periphery of the honeycomb assembly; circulating fluid in the industrial gas turbine in a space between the support housing and the rotating shaft, the circulated fluid possessing pressure fluctuations, the tooth and the honeycomb assembly each being positioned between the circulating fluid and the brush seal; and contacting the honeycomb assembly with the annular tooth in the groove so as to reduce exposure of the brush seal to the pressure fluctuations in the circulated fluid.
In accordance with a further aspect, the invention provides a brush seal assembly for reducing adverse fluid flow effects to a brush seal, the brush seal assembly comprising a support housing having a passage; a rotating shaft disposed in the passage of the support housing, the rotating shaft including a shaft body having a periphery and an annular tooth extending around the periphery of the shaft body; an annular brush seal including a plurality of bristles extending around the shaft body, each of the plurality of bristles attached to and extending from the support housing in the passage towards the rotating shaft; and means for reducing adverse fluid flow effects to the brush seal having a groove extending around an inner periphery thereof, the means for reducing disposed in the passage around, and proximate to, the tooth of the rotating shaft such that the tooth of the rotating shaft is disposed in the groove.
In accordance with a yet further aspect, the invention provides a brush seal assembly for reducing adverse fluid flow effects to a brush seal in a gas turbine, the brush seal assembly comprising a support housing having a passage; a rotating shaft disposed in the passage of the support housing, the rotating shaft including a shaft body having a periphery and an annular tooth extending around the periphery of the shaft body, the tooth including a base portion and a contact portion; an annular brush seal including a plurality of bristles extending around the shaft body, each of the plurality of bristles attached to and extending from the support housing in the passage towards the rotating shaft; and means for reducing adverse fluid flow effects to the brush seal having a groove extending around an inner periphery thereof, the means for reducing disposed in the passage around, and proximate to, the tooth of the rotating shaft such that the tooth of the rotating shaft is disposed in the groove, the means for reducing disposed adjacent to the brush seal.